Crimping connector means for fine wires

ABSTRACT

A crimpable barrel, usually with a serrated, burled or other type irregular shaped inner surface is crimped around a piece of elastomeric material after a fine wire has been layed in between the elastomeric material and the inner surface of the barrel. This type crimp connection will break away the varnish or shellac type insulation on the fine wire and make good electrical connection with the barrel, without breaking or appreciably damaging the structural strength of the wire.

United States Patent 1191 m1 Weidler Aug. 5, 1975 4] CRIMPING CONNECTOR MEANS FOR FINE 3.836,)4l 9/1974 lzraeli 339/95 R WIRES 4 Primary E.\'uminer.loseph H. McGlynn 751 .ChlH Wdl,L tr i nvtmor Pa ar es a") 8 er dncds er Attorney, Agent, or FirmW|ll1am .li Keatlng, Esq.;

Donald W. Phillion, Esq. [73] Assignee: AMP Incorporated, Harrisburg, Pa.

[22] Filed: July 17, 1974 [57] ABSTRACT [2!] Appl No.: 489,230 A crimpable barrel, usually with a serrated. burled or other type irregular shaped inner surface is crimped around a piece of elastomeric material after a fine 3? z g wire has been layed in between the elastomeric mate 3 97 99 rial and the inner surface of the barrel. This type i l le 9 "53 1 crimp connection will break away the varnish 0r shellac type insulation on the fine wire and make and g electrical connection with the barrel. without breaking [56] References Cited or appreciably damaging the structural strength of the UNITED STATES PATENTS Mfg 3 4lO.95O 11/1968 Fredenberg .i l74/84 C 3,649,954 3/1972 Kurtz .9 339/95 R 19 clalms- 9 Drawlng Flgures PATENTEU AUE 51975 SHEET 1 PATENTED AUG 51975 SHEU 1 CRIMPING CONNECTOR MEANS FOR FINE WIRES BACKGROUND OF THE INVENTION This invention relates generally to crimp-type concrimping can be accomplished in a manner wherein the nectors and more particularly to crimp-type connectors for use with very fine and fragile wires.

Certain type wires, such as magnet wires frequently employed in electric motors, are very fragile and difcult to connect to other wires, either directly or by means of connectors. Furthermore, magnet wires are ordinarily coated with an insulating varnish, shellac or other material which must either be removed or penetrated in order to make an electrical connection.

Conventional metal crimp connectors must be crimped within a rather critical force range when used with these fine magnet wires. A little too much crimping force often will either break the fine wire or at least weaken it to the extent that breakage will occur later. If the crimping force is too light, the varnish insulation will not be effectively penetrated and the proper electrical and/or mechanical connection will not be made.

Since many electric motors are permanently sealed within some type of encapsulation the failure of one small magnet wire will often result in the waste of the entire motor.

Other applications requiring connection of very fine wires, either with or without a varnish or shellac type insulation, are widely used and known to those skilled in the art.

BRIEF STATEMENT OF THE INVENTION It is a primary object of the present invention to provide a crimptype connector which effectively will make an electrical and a mechanical bond with a fine wire without any significant weakening of the wire strength.

A second purpose of the invention is to provide an inexpensive and reliable crimping connector for crimping a fine wire.

A third object of the invention is to provide a crimptype connector which will effectively and consistently penetrate the varnish insulation on a magnet wire but yet will not substantially structurally weaken the wire.

A fourth object of the invention is the improvement of crimping connectors for crimping fine wires generally.

In accordance with a preferred embodiment of the invention, there is provided a crimping barrel which contains an elastomeric compound therein. The inner wall of the barrel can comprise serrations substantially perpendicular to the main axis of the barrel. The fine magnet wire to be crimped is layed inside the barrel between the inner surface of the barrel and the elastomeric material, and crimping is then effected. The serrations on the barrel function to press the fine wire into the resilient elastomeric material in such a fashion that as the wire tends to conform to the contour of the profile of the serrations, portions of it will be pushed into the valleys between the serrations, thereby dragging the fine wire across these serrations, scraping away the insulating varnish, to make a good electrical connection between the conductive wire under the insulating varnish and the serrations on the metal barrel. At the same time, because of the resiliency and softness of the elastomeric material, the force exerted along the wire will be quite uniform and will not be concentrated on any least force exerted between the serrations on the inner surface of the barrel and the elastomeric material is at the point where the wire enters the barrel. This force between the elastomeric material and the serrations gradually increases along the length of the wire as it extends further into said barrel. In this form of the invention a smaller strain is placed on the wire where it enters the connector than if the force between the serrations and the elastomeric material were constant along the length of the barrel.

BRIEF DESCRIPTION OF THE DRAWINGS The above-mentioned and other objects and features of the invention will be more fully understood from the following detailed description thereof when read in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view ofa basic crimping barrel containing an elastomeric material and a magnet wire inserted therebetween before crimping occurs;

FIG. 2 shows the structure of FIG. 1 after crimping has occurred;

FIG. 2a is a sectional view of the structure of FIG. 2 taken along the plane A-A;

FIG. 3 shows a blank form of a connector, one end of which is designed to receive an elastomeric material and a fine wire and then to be crimped, and the other end of which is designed to crimp over a larger conductor;

FIG. 4 shows the structure of FIG. 3 formed into its precrimping shape, with the elastomeric material positioned therein;

FIG. 5 shows the structure of FIG. 4 with the fine wires crimped in one end thereof against the elastomeric material, and a larger conductor crimped within a barrel at the other end of the conductor;

FIG. 6 shows a blank of another form of a connector, one end of which is adapted to crimp a fine wire with the aid of an elastomeric material, and the other end of which is designed to crimp a larger conductor in a conventional manner;

FIG. 7 is a perspective view of the blank of FIG. 6 formed into the pre-crimped state; and

FIG. 8 shows the structure of FIG. 7 with fine magnet wires crimped in one end thereof against an elastomeric material, and a larger conductor crimped in a more usual manner at the other end thereof.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. I, a barrel 10 has a series of serrations II inside the barrel. A piece of elastomeric material I2, which can be almost any type of rubberlike or elastic material, is placed in the barrel I0. Then the fine wire 12, which can be a magnet wire, is slid down the side of the barrel 10 between serrations II on the side of the barrel I0 and the elastomeric material 12.

In FIG. 2 the structure of FIG. 3 is shown after crimping has occurred. It can be seen that the barrel 10 has been forced against the elastomeric material 12 to press the magnet wire 13 snugly between the serrations 11 (not visible in FIG. 2) of barrel 10, and the elastomeric material 12.

During the crimping operation the wire 13 is forced down into the several serrations 11, as can be seen in FIG. 2A, which is a sectional view of FIG. 2 down along the plane A-A. As the wire 13 is forced down against the inner side of the barrel l0, in-between the indented serrations I] and the elastomeric material 12, the wire 13 is stretched because of the serrations 11 and the varnish insulation thereon is broken up and scraped away so as to provide a good electrical connection between the wire 13 and the serrations 11.

Going now to FIGS. 3, 4 and there is shown a different form of the invention wherein the barrel is substantially completely encircled around the elastomeric material and the magnet wires after crimping.

More specifically, FIG. 3 shows a blank of a connector having serrations 15 therein. The blank of FIG. 3 is stamped into the form shown in FIG. 4, into which an elastic material 17 is stuffed to form a space 18 be tween the inside of the barrel l9 and the elastomeric material 17. Fine magnet wires, such as wires and 21, are then inserted in this gap 18. At the other end of the connector there is provided another noncrimped U-shaped element 16 into which a larger conductor 22 is inserted.

Both ends 19 and 16 of the connector are crimped to produce the results shown in FIG. 5. The magnet wires 20 and 21, which were inserted or pushed into gap 18, are now firmly squeezed between the elastomeric material l7 and the serrations 15 (which are not visible in FIG. 5), on the inner surface of crimped barrel l9. The other end 16 of the connector of FIG. 5 is crimped around the bared end of conductor 22, the remainder of conductor 20 being covered by an insulating sleeve 23.

If desired, the crimping force employed to crimp the barrel 19 can be the least near the points where the two fine wires 20 and 21 enter the barrel, i.e., at the left of the crimped barrel 19 shown in FIG. 5. Then, as the wires extend into the barrel the crimping force can have been made to be increasingly greater so that after crimping the force exerted on the wires 20 and 21 increase as the wire extends increasingly further into the barrel 19. With the foregoing arrangement the probability of the wire breaking due to the force exerted thereon by the crimped connector barrel becomes even less than the already small probability of wire breakage where the crimping force is uniform along the entire length of the barrel. It can be seen that in FIG. 2 this feature of increasing the pressure on the wire as it extends further into the crimped barrel is inherent.

Referring now to FIGS. 6, 7 and 8, there is shown still another modification of the invention. In FIG. 6 there is shown the blank of the connector which contains serrations and 31. When stamped into its precrimped condition, the connector is as shown in FIG. 7, with a barrel 32 at one end thereof and a U-shaped element 33 at the other end thereof. Within the barrel 32 is placed an elastomeric material 34. A curved section of the barrel 32 is formed to define a gap 36 between the elastomeric material 34 and the section 35, with the ends of this curved section 35 coming into contact with the elastomeric material 34 so as to laterally confine the fine wires and 41 which are inserted in the gap 36 before crimping takes place.

A tang 37 is cut from the wall of the barrel 32 and extends inwardly into barrel 32 to grip the ends of magnet wires inserted in the gap 36 and to further assist in holding said magnet wires 40 and 41 until crimping occurs.

In FIG. 8 the connector of FIGS. 6 and 7 is shown in its crimped form with the fine magnet wires 40 and 41 being held securely in the now closed gap 36 between the inner surface of the barrel 32 and the elastomeric material 34, which closed gap 36 has been formed by the crimping of barrel 32.

Because of the serrations 30 and 31 on the inner surface of barrel 32 the varnish insulation on the magnet wires 40 and 41 is broken up and scraped away as discussed in connection with FIGS. 1-5. At the other end of the connector of FIG. 8 the barrel 33 is shown crimped around the end of conductor 43 from which the insulating sleeve 44 has been removed.

It is to be understood that the basic inventive concept involves the employment of a crimpable barrel containing an elastomeric material between which is placed a wire, usually fragile and which can have a varnish or other insulative type coating, or can be a bare wire. The inside of the barrel can be serrated, scored, burled, or configured in many other ways, all designed to cause the magnet wires to be pressed therein by the elastomeric resilient material and thereby break and/or scrape away the insulation on the wires and make both a good electrical connection and a good mechanical bond between the wire and the barrel.

Other forms of the invention will be readily apparent to those skilled in the art and are intended to be included within the scope and spirit of the invention described herein.

What is claimed is:

l. A crimp type connector for connecting to a fragile wire comprising:

a conductive metal barrel having an irregularly formed inner surface; and

elastomeric material positioned in said barrel and gripped firmly by said barrel when said barrel is crimped;

said fragile wire positioned securely between said elastomeric material and the irregularly formed inner surface of said barrel and forced to follow generally the irregularly formed inner surface of said metal barrel when said barrel is crimped.

2. A crimp type connector in accordance with claim 1 in which the force exerted on said fragile wire between said barrel and said piece of elastomeric material is the least near the point where said fragile wire enters said barrel and increases as the depth said wire extends into the barrel increases.

3. A crimp type connection in accordance with claim 1 in which said fragile wire comprises an insulative layer thereon constructed to become removed from portions of said wire in response to the forcing of said wire into said irregularly formed inner surface of said barrel to create an electrical connection between said wire and said barrel.

4. A crimp type connector in accordance with claim 3 comprising a contact means connected to said barrel and constructed to make electrical contact with a third conductive element.

5. A crimp type connector in accordance with claim 3 in which the force which is exerted on said fragile wire between said barrel and said piece of elastomeric material is the least near the point where said fragile wire enters said barrel and increases as the depth said wire extends into the barrel increases.

6. A crimp type connection between a wire and metal connector comprising:

an electrically conductive barrel having concave and convex portions on the inner surface thereof;

a piece of elastomeric material within said barrel;

said wire comprising a coating of insulative material;

said wire being positioned between said inner surface of said barrel and said piece of elastomeric material; and

being forced at least partially into the concave portions of said barrel inner surface by said elastomeric material when said metal barrel is crimped against said elastomeric material.

7. A crimp type connector in accordance with claim 6 in which the force which is exerted on said wire between said barrel and said piece of elastomeric material is the least near the point where said wire enters said barrel and increases as the depth said wire extends into the barrel increases.

8. A crimp type connector in accordance with claim 7 comprising a contact means connected to said barrel and constructed to make electrical contact with a third conductive element.

9. A crimp type connection in accordance with claim 6 in which said insulative coating on said wire is constructed to become removed from portions of said wire in response to the forcing of said wire into said concave portions of said inner surface of said barrel to create an electrical connection between said wire and said barrel.

10. A crimp type connector in accordance with claim 9 in which the force which is exerted on said wire between said barrel and said piece of elastomeric material is the least near the point where said wire enters said barrel and increases as the depth said wire extends into the barrel increases.

ll. A crimp type connection between a wire and metal connector comprising:

a conductive barrel with its inner surface having an irregularly shaped configuration with raised and depressed portions;

21 rubber-like element within said barrel;

said wire being positioned between said inner surface of said barrel and said rubber-like element and being forced to generally follow the said irregularly shaped configuration of said inner surface of said barrel due to the force exerted thereon by said rubber-like element when said barrel is crimped against said rubber-like element.

12. A crimp type connection in accordance with claim 11 in which said wire comprises an insulative layer thereon constructed to become removed from portions of said wire in response to the forcing of said wire to generally follow the irregularly shaped configuration of said inner surface of said barrel to create an electrical connection between said wire and said barrel.

13. A crimp type connector in accordance with claim 12 in which the force which is exerted on said wire be tween said barrel and said piece of rubber-like element is the least near the point where said wire enters said barrel and increases as the depth said wire extends into the barrel increases.

14. A crimp type connector in accordance with claim 12 comprising a contact means connected to said barrel and constructed to make electrical contact with a third conductive element.

15. A crimp type connector in accordance with claim 11 in which the force which is exerted on said wire between said barrel and said rubber-like element is the least near the point where said wire enters said barrel and increases as the depth said wire extends into the barrel increases.

16. A method for connecting fragile wires to a connector comprising the steps of:

positioning a piece of elastomeric material within a metal barrel having an irregularly shaped inner sur face;

placing said fragile wire in between said piece of elastomeric material and said irregularly shaped inner surface of said barrel; and

crimping said barrel to squeeze said fragile wire in between said irregularly shaped inner surface of said barrel and piece of elastomeric material to make an electrical connection between said barrel and said fine fragile wire.

17. A method for connecting wires having a thin insu lating coating to a connector comprising the steps of:

positioning a piece of elastomeric material within a conductive barrel having an irregularly shaped inner surface;

placing said wire in-between said piece of elastomeric material and said irregularly shaped inner surface of said barrel; and

crimping said barrel to squeeze said wire in-between said irregularly shaped inner surface of said barrel and piece of elastomeric material to remove portions of said insulative coating from said wire and to make an electrical connection between said barre] and said wire.

18. A method for connecting wires to a connector comprising the steps of:

positioning a piece of elastomeric material within a metal barrel having an inner surface; placing said wire in between said piece of elastomeric material and said inner surface of said barrel; and

crimping said barrel to squeeze said wire in between said inner surface of said barrel and piece ofelastomeric material to make an electrical connection between said barrel and said wire.

19. A method for connecting wires to a connector comprising the steps of:

positioning a piece of elastomeric material within a metal barrel having an inner surface;

placing said wire in between said piece of elastomeric material and said inner surface of said barrel; and crimping said barrel to squeeze said wire in between said inner surface of said barrel and piece of elastomeric material with the least crimping force being applied where the wire enters the barrel and increasing as the wire extends further into the barrel, to make an electrical connection between said barrel and said wire. 

1. A crimp type connector for connecting to a fragile wire comprising: a conductive metal barrel having an irregularly formed inner surface; and elastomeric material positioned in said barrel and gripped firmly by said barrel when said barrel is crimped; said fragile wire positioned securely between said elastomeric material and the irregularly formed inner surface of said barrel and forced to follow generally the irregularly formed inner surface of said metal barrel when said barrel is crimped.
 2. A crimp type connector in accordance with claim 1 in which the force exerted on said fragile wire between said barrel and said piece of elastomeric material is the least near the point where said fragile wire enters said barrel and increases as the depth said wire extends into the barrel increases.
 3. A crimp type connection in accordance with claim 1 in which said fragile wire comprises an insulative layer thereon constructed to become removed from portions of said wire in response to the forcing of said wire into said irregularly formed inner surface of said barrel to create an electrical connection between said wire and said barrel.
 4. A crimp type connector in accordance with claim 3 comprising a contact means connected to said barrel and constructed to make electrical contact with a third conductive element.
 5. A crimp type connector in accordance with claim 3 in which the force which is exerted on said fragile wire between said barrel and said piece of elastomeric material is the least near the point where said fragile wire enters said barrel and increases as the depth said wire extends into the barrel increases.
 6. A crimp type connection between a wire and metal connector comprising: an electrically conductive barrel having concave and convex portions on the inner surface thereof; a piece of elastomeric material within said barrel; said wire comprising a coating of insulative material; said wire being positioned between said inner surface of said barrel and said piece of elastomeric material; and being forced at least partially into the concave portions of said barrel inner surface by said elastomeric material when said metal barrel is crimped against said elastomeric material.
 7. A crimp type connector in accordance with claim 6 in which the force which is exerted on said wire between said barrel and said piece of elastomeric material is the least near the point where said wire enters said barrel and increases as the depth said wire extends into the barrel increases.
 8. A crimp type connector in accordance with claim 7 comprising a contact means connected to said barrel and constructed to make electrical contact with a third conductive element.
 9. A crimp type connection in accordance with claim 6 in which said insulative coating on said wire is constructed to become removed from portions of said wire in response to the forcing of said wire into said concave portions of said inner surface of said barrel to create an electrical connection between said wire and said barrel.
 10. A crimp type connector in accordance with claim 9 in which the force which is exerted on said wire between said barrel and said piece of elastomeric material is the least near the point where said wire enters said barrel and increases as the depth said wire extends into the barrel increases.
 11. A crimp type connection between a wire and metal connector comprising: a conductive barrel with its inner surface having an irregularly shaped configuratiOn with raised and depressed portions; a rubber-like element within said barrel; said wire being positioned between said inner surface of said barrel and said rubber-like element and being forced to generally follow the said irregularly shaped configuration of said inner surface of said barrel due to the force exerted thereon by said rubber-like element when said barrel is crimped against said rubber-like element.
 12. A crimp type connection in accordance with claim 11 in which said wire comprises an insulative layer thereon constructed to become removed from portions of said wire in response to the forcing of said wire to generally follow the irregularly shaped configuration of said inner surface of said barrel to create an electrical connection between said wire and said barrel.
 13. A crimp type connector in accordance with claim 12 in which the force which is exerted on said wire between said barrel and said piece of rubber-like element is the least near the point where said wire enters said barrel and increases as the depth said wire extends into the barrel increases.
 14. A crimp type connector in accordance with claim 12 comprising a contact means connected to said barrel and constructed to make electrical contact with a third conductive element.
 15. A crimp type connector in accordance with claim 11 in which the force which is exerted on said wire between said barrel and said rubber-like element is the least near the point where said wire enters said barrel and increases as the depth said wire extends into the barrel increases.
 16. A method for connecting fragile wires to a connector comprising the steps of: positioning a piece of elastomeric material within a metal barrel having an irregularly shaped inner surface; placing said fragile wire in between said piece of elastomeric material and said irregularly shaped inner surface of said barrel; and crimping said barrel to squeeze said fragile wire in between said irregularly shaped inner surface of said barrel and piece of elastomeric material to make an electrical connection between said barrel and said fine fragile wire.
 17. A method for connecting wires having a thin insulating coating to a connector comprising the steps of: positioning a piece of elastomeric material within a conductive barrel having an irregularly shaped inner surface; placing said wire in-between said piece of elastomeric material and said irregularly shaped inner surface of said barrel; and crimping said barrel to squeeze said wire in-between said irregularly shaped inner surface of said barrel and piece of elastomeric material to remove portions of said insulative coating from said wire and to make an electrical connection between said barrel and said wire.
 18. A method for connecting wires to a connector comprising the steps of: positioning a piece of elastomeric material within a metal barrel having an inner surface; placing said wire in between said piece of elastomeric material and said inner surface of said barrel; and crimping said barrel to squeeze said wire in between said inner surface of said barrel and piece of elastomeric material to make an electrical connection between said barrel and said wire.
 19. A method for connecting wires to a connector comprising the steps of: positioning a piece of elastomeric material within a metal barrel having an inner surface; placing said wire in between said piece of elastomeric material and said inner surface of said barrel; and crimping said barrel to squeeze said wire in between said inner surface of said barrel and piece of elastomeric material with the least crimping force being applied where the wire enters the barrel and increasing as the wire extends further into the barrel, to make an electrical connection between said barrel and said wire. 